A good method of discovery is to imagine certain members of a system removed and then see how what is left would behave: for example, where would we be if iron were absent from the world: this is an old example.

With prophecies the commentator is often a more important man than the prophet.

The worst thing you can possibly do is worrying and thinking about what you could have done.

He marvelled at the fact that the cats had two holes cut in their fur at precisely the spot where their eyes were.

What you have been obliged to discover by yourself leaves a path in your mind which you can use again when the need arises.

He was always smoothing and polishing himself, and in the end he became blunt before he was sharp.

God creates the animals, man creates himself.